How Big Things Get Done: The Surprising Factors That Determine the Fate of Every Project, from Home Renovations to Space Exploration and Everything In Between

by Bent Flyvbjerg

I call the pattern followed by the Empire State Building and other successful projects “Think slow, act fast.”

In every big project, there are blizzards of numbers generated at different stages by different parties. Finding the right ones—those that are valid and reliable—takes skill and work.

So how often do projects deliver

as promised? That is the most straightforward question anyone could ask.

“Project estimates between 1910 and 1998 were short of the final costs an average of 28 percent,” according to The New York Times, summarizing our findings. “The biggest errors were in rail projects, which ran, on average, 45 percent over estimated costs [in inflation-adjusted dollars]. Bridges and tunnels were 34 percent over; roads, 20 percent. Nine of 10 estimates were low, the study said.”[7] The results for time and benefits were similarly bad.

But otherwise it was a broadly similar story

of cost and schedule overruns and benefit shortfalls.

These IT projects are made of code, not steel and concrete. They would seem to be different from transportation infrastructure in every possible way. So why would their outcomes be statistically so similar, with consistent cost and schedule overruns and benefit shortfalls?

The pattern was so clear that I started calling it the “Iron Law of Megaprojects”: over budget, over time, under benefits, over and over again.

the general story remains the same: In total, only 8.5 percent of projects hit the mark on both cost and time. And a minuscule 0.5 percent nail cost, time, and benefits. Or to put that another way, 91.5 percent of projects go over budget, over schedule, or both.

And 99.5 percent of projects go over budget, over schedule, under benefits, or some combination of these. Doing what you said you would do should be routine, or at least common. But it almost never happens.

let’s say you are an unusually cautious person and you are planning the construction of a large building. You put a 20 percent buffer into the budget and think you are now well protected. But then you come across my research and discover that the actual mean cost overrun of a major building project is 62 percent. That is heart-stopping. It may also be project-stopping.

Wealth, for example, is fat-tailed. At the time of writing, the wealthiest person in the world is 3,134,707 times wealthier than the average person. If human height followed the same distribution as human wealth, the tallest person in the world would not be 1.6 times taller than the average person; he would be 3,311 miles (5,329 kilometers) tall, meaning that his head would be thirteen times farther into outer space than the International Space Station.

To illustrate, 18 percent of IT projects have cost overruns above 50 percent in real terms. And for those projects the average overrun is 447 percent! That’s the average in the tail, meaning that many IT projects in the tail have even higher overruns than this. Information technology is truly fat-tailed!

But for now the lesson is simple, clear, and scary: Most big projects are not merely at risk of not delivering as promised. Nor are they only at risk of going seriously wrong. They are at risk of going disastrously wrong because their risk is fat-tailed.

Nassim Nicholas Taleb famously dubbed low-probability, high-consequence events “black swans.” Disastrous project outcomes such as these can end careers, sink companies, and inflict a variety of other carnage. They definitely qualify as black swans.

If you are not a corporate executive or government official, and if the ambitious project you are contemplating is on a much smaller scale than these giants, it may be tempting to think that none of this applies to you. Resist that temptation.

My data show that smaller projects are susceptible to fat tails, too. Moreover, fat-tailed distributions, not normal distributions, are typical within complex systems, both natural and human, and we all live and work within increasingly complex systems, which means increasingly interdependent systems.

Projects that fail tend to drag on, while those that succeed zip along and finish.

Why is that? Think of the duration of a project as an open window. The longer the duration, the more open the window. The more open the window, the more opportunity for something to crash through and

cause trouble, including a big, ba...

But the more time that passes from the decision to do a project to its delivery, the greater their probability.

It’s hard to think of anything more trivial to most people around the world than gusts of wind in the Egyptian desert. Yet on March 23, 2021, it was just such gusts, at just the wrong moment, that pushed the bow of Ever Given, a giant container ship, into a bank of the Suez Canal. The ship got stuck and couldn’t be budged for six days, blocking the canal, halting hundreds of ships, freezing an estimated $10 billion in trade each day, and sending shocks rippling through global supply chains.

that the dynamic interdependencies among the parts of the system—the wind, the canal, the ship, and supply chains—created strong nonlinear responses and amplification.

minor changes combined in a way to produce a disaster.

“For want of a nail, the shoe was lost. For want of a shoe, the horse was lost. For want of a horse, the rider was lost. For want of a rider, the battle was lost. For want of a battle, the kingdom was lost.” This version was published by Benjamin Franklin in 1758, and he introduced it with the warning that “a little neglect may breed great mischief.”

From the dramatic to the mundane to the trivial, change can rattle or ruin a project—if it occurs during the window of time when the project is ongoing. Solution? Close the window. Of course, a project can’t be completed instantly, so we can’t close the window entirely. But we can make the opening radically smaller by speeding up the project and bringing it to a conclusion faster. That is a main means of reducing risk on any project. In sum, keep it short!

Planning is a safe harbor. Delivery is venturing across the storm-tossed seas.

That’s essential, Catmull noted, because production “is where costs explode.”

Not only is it safer for planning to be slow, it is good for planning to be slow, as the directors at Pixar well know. After all, cultivating ideas and innovations takes time. Spotting the implications of different

options and approaches takes more time. Puzzling through complex problems, coming up with solutions, and putting them to the test take still more time. Planning requires thinking—and creative, critical, careful thinking is slow. Abraham Lincoln is reputed to have said that if he had five minutes to chop down a tree, he’d spend the first three sharpening the ax.[29] That’s exactly the right approach for big projects: Put enormous care and ef...

PROJECTS DON’T GO WRONG, THEY START WRONG

how the movie studio and others use simulation and iteration to produce a plan that is creative, rigorous, detailed, and reliable—and highly likely to make delivery smooth and swift. I’ll use “Pixar planning” as a name and a model for planning, not just at Pixar but for any planning that develops a tested and tried plan; that is, a plan worthy of its name.

In chapter 6, it’s on to forecasting. How long will the project take? How much will it cost? Setting the wrong expectations at the start can set you up for failure before you’ve even started. Fortunately, there is a fix. More fortunately, it’s surprisingly easy.

get better results when people take a leap of faith, get started right away, and rely on ingenuity to see them through.

I’ll draw on the themes of the previous chapters to explore a concept that brings them all together: modularity. Its potential is huge. Not only can it cut costs, boost quality, and speed things up for a vast array of projects from wedding cakes to subways, it can transform how we build infrastructure—and even help save the world from climate change.

THE COMMITMENT FALLACY If “Think slow, act fast” is the wise approach to big projects, why do so many people do the exact opposite? Because they rush to commit. You do need to commit. But not in the way you think.

The Pentagon: A History, a superb chronicle of the building’s construction.

Draft a plan for an office building of five hundred thousand square feet, twice as much as in the Empire State Building. But it can’t be a skyscraper; that would take too much steel at a time when steel is needed for ships and tanks.

And it can’t be in the District of Columbia; there is no room. It has to be across the Potomac River in Virginia, on the site of a recently abandoned airfield.

it is fundamentally typical of how big projects come together. Purposes and goals are not carefully considered. Alternatives are not explored. Difficulties and risks are not

investigated. Solutions are not found. Instead, shallow analysis is followed by quick lock-in to a decision that sweeps aside all the other forms the project could take. “Lock-in,” as scholars refer to it, is the notion that although there may be alternatives, most people and organizations behave as if they have no choice but to push on, even past the point where they put themselves at more cost or risk than they would have accepted at the start. This is followed by action. And usually, sometime after that, by trouble; for instance, in the guise of the “break-fix cycle”

is. “Act in haste, repent at leisure” is a centuries-old chestnut.

Tattoos, marriages, big projects: In every case, we know we really should think it through carefully, so why do we so often fail to do so?

In Kahneman’s laboratory experiments, the stakes are low. There is typically no jockeying for position, no competition for scarce resources, no powerful individuals or organizations, no politics of any kind.

But the intuitive judgments generated by System One are not experienced as emotions. They simply “feel” true.

For us to be so consistently wrong, we must consistently ignore experience. And we do, for various reasons. When we think of the future, the past may simply not come to mind and we may not think to dig it up because it’s the present and future we are interested in. If it does surface, we may think “This time is different” and dismiss it (an option that’s always available because, in a sense, every moment in life is unique). Or we may just be a little lazy and prefer not

to bother, a preference well documented in Kahneman’s work. We all do this.

That’s because, in constructing the scenario, you only imagine yourself working. That narrow focus excludes all the people and things around you that could intrude on your work time. In other words, you are imagining a “best-case” scenario. That’s typical. When people are asked to make a “best-guess” scenario—the scenario most likely to occur—what they come up with is generally indistinguishable from what they settle on when asked for a “best-case” scenario.[20]

When this bias for action is generalized into the culture of an organization, the reversibility caveat is usually lost. What’s left is a slogan—“Just do it!”—that is seemingly applicable in all situations.